Gastroenterology II: lower GI disorders

Sudden, severe, persistent abdominal pain

Pain out of proportion to exam (mesenteric ischemia)

Nausea, vomiting, anorexia

Obstipation (no stool or flatus, obstruction)

symptoms associated with a acute/surgical abdomen

Cholecystitis, cholangitis, hepatitis, biliary colic, Fitz-Hugh-Curtis

DDx of RUQ pain

Splenic infarct/rupture, gastritis, pancreatitis, pneumonia

DDx of LUQ pain

Peptic ulcer disease, pancreatitis, MI, aortic aneurysm

DDX of epigastric pain

Early appendicitis, small bowel obstruction, mesenteric ischemia

DDx of periumbical pain

Appendicitis, Crohn's, ectopic pregnancy, ovarian torsion

DDx of RLQ pain

Diverticulitis, ovarian torsion, ectopic pregnancy

DDx of LLQ pain

Peritonitis, bowel obstruction, mesenteric ischemia, gastroenteritis

DDx of diffuse abdominal pain

peritonitis

Rebound + guarding +diffuse abdominal pain=

Cholecystitis/cholangitis

History: RUQ pain, worse after fatty meals, fever, nausea.

Charcot triad

RUQ pain, jaundice, fever/chills

associatedd with cholangitis

pancreatitis

History: Epigastric pain radiating to back, better leaning forward, N/V.

mesenteric ischemia

History: Severe pain out of proportion to exam, risk factors (AFib, atherosclerosis).

Labs: ↑ Lactate, metabolic acidosis.

perforated ulcer

History: Sudden severe epigastric pain.

Exam: Rigid abdomen, rebound, guarding.

Labs/Imaging: Leukocytosis, free air under diaphragm (upright CXR).

Bowel rest (clear liquid diet, advance as tolerated).

Oral antibiotics (covering Gram-negative + anaerobes, e.g., ciprofloxacin + metronidazole or amoxicillin-clavulanate).

Outpatient if stable.

management of acute uncomplicated diverticulitis

NPO, IV fluids, IV antibiotics.

Abscess drainage (percutaneous).

Surgery if perforation, fistula, or obstruction.

management of complicated diverticulitis (abscess, perforation, obstruction, peritonitis)

irritable bowel syndrome

Definition: Functional bowel disorder with chronic abdominal pain/discomfort + altered bowel habits (no structural cause).

Recurrent abdominal pain ≥1 day/week for 3 months, associated with ≥2 of: related to defecation, change in stool frequency, change in stool form

Rome IV criteria for diagnosis of IBS

infectious: Fever, chills, myalgias, nausea, vomiting

non-infectious: Bloating, weight loss, nocturnal diarrhea (IBD/malabsorption)

associated symptoms of infectious vs non-infectious diarrhea

infectious: Watery (viral, toxigenic bacteria) or bloody (invasive bacteria)

non-infectious: Fatty (steatorrhea in malabsorption) or mucus (IBS/IBD)

stool features of infectious vs non-infectious diarrhea

Sudan stain, 72-hour fecal fat collection

test for stool fat, indicating steatorrhea

D-xylose test

abnormal absorption suggests mucosal disease (celiac);

normal absorption if pancreatic insufficiency.

location: Colon only (always involves rectum), continuous

depth: mucosal and submucosal only

endoscopy: friable mucosa, continuous ulcerations

location, depth, and endoscopic findings of UC

location: any part of GI tract, skip lesions

depth: transmurall

endosccopy: cobblestoning, strictures, fistula

location, depth, and endoscopic findings of crohn's disease

ulcerative colitis

histologgy: crypt abscesses, NO granulomas

crohn's disease

histology: noncaseating granulomas

Toxic megacolon, ↑ colorectal cancer risk

complications associated with UC

Fistulas, abscesses, strictures, malabsorption

complications associated with crohn's

Both can have arthritis, uveitis, erythema nodosum, pyoderma gangrenosum

extraintestinal effects associated with UC and crohn's

UC: smoking is protective

Crohns: smoking is a risk factor

the role of smoking in UC vs Crohn's

mild-moderate: 5-ASA (mesalamine, sulfasalazine)

severe: corticosteroids, bowel rest, biologics

treatment of acute exacerbation of IBD

Aminosalicylates (UC > CD).

Immunomodulators: azathioprine, 6-MP, methotrexate.

Biologics: anti-TNF (infliximab), anti-integrin (vedolizumab), anti-IL (ustekinumab).

maintenance therapy indicated for IBD

Chronic diarrhea, steatorrhea (bulky, greasy stools), bloating, flatulence, weight loss.

general symptoms of malabsorptive syndromes

Autoimmune deposition of IgA at the tips of dermal papillae

GI pathology (GERD, gastritis, IBD, hepatitis, pancreatitis) often causes inflammation and congestion

→ lymphatic drainage helps reduce edema and improve immune response.

rationale for lymphatic manipulative techniques in GI dysfunctions

>3mm thickness suggests pathology

define colonic wall thickening on radiographs

-IBD, infectious colitis, ischemic colitis

-colorectal carcinoma

-venous congestion

-toxic megacolon

DDx of colonic wall thickening on radiograph

thumbprinting GI

sign of mucosal edema/hemorrhage (ischemia, infection, IBD).

IBD, infectious colitis

symmetric long segment thickening on abdominal radiograph suggests

malignancy

asymmetric/focal irrregular thickening on colon radiograph inddicates

colonoscopy with biopsy

gold standard diagnostic test for IBD

CT enterography

specialized CT evaluation of the small bowel after the oral administration of low-density (0.1%) barium.

Outlines GI lumen → differentiates bowel from adjacent structures.

Used for suspected perforation, abscess, fistula, tumor.

indications for oral contrast in abddominal CT

Useful for distal colon/rectum evaluation.

Indications: suspected anastomotic leak, diverticulitis, distal obstruction.

indications for rectal contrast in abdominal CT

Highlights vascular structures & enhances solid organs.

Essential for ischemia, abscess, tumor, trauma, appendicitis, diverticulitis.

indications for IV contrast for abdominal CT

Adhesions, hernia, tumor, strictures

etiologies of SBO

SBO: Colicky abdominal pain, vomiting, distension, obstipation

ileus: distension, obstipation

Diffuse, mild abdominal discomfort, distension

symptoms of SBO vs ileus

High-pitched, hyperactive bowel sounds early → silent if late

exam findings associated with SBO

small bowel obstruction XR

Dilated small bowel loops (>3 cm), air-fluid levels, "step-ladder pattern," transition point

Post-op, meds (opioids), infection, electrolyte imbalance

etiologies of ileus

Hypoactive or absent bowel sounds

exam findings of ileus

ileus on XR

Diffuse bowel dilation (small + large bowel), no clear transition point

Functional, usually resolves with supportive care

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Treatment	Indication / Purpose
NPO initially	Bowel rest if significant distension, nausea, or vomiting
IV fluids	Correct dehydration and maintain hydration
Electrolyte correction	Correct hypokalemia and hypomagnesemia
NG tube decompression	Significant vomiting or abdominal distension
Stop opioids / anticholinergics	Medications that decrease bowel motility
Early ambulation	Stimulates GI motility
Early oral feeding as tolerated	Promotes recovery in uncomplicated postoperative ileus
Treat underlying cause	Infection, inflammation, metabolic abnormalities

clinical course of ileus

Clear liquid diet 24 hrs prior.

Bowel prep with laxatives/enema the night before.

NPO after midnight.

patient prep for a barium enema

-arterial emobolus (AFib, MI, valvular disease)

-Arterial thrombosis

-venous thrombosis

-hypotension, vasopressors

etiologies of ischemic bowel

acute ischemic bowel

Sudden severe abdominal pain out of proportion to exam.

Nausea, vomiting, diarrhea (may be bloody

Leukocytosis.

↑ Lactate & metabolic acidosis (late finding).

Possible elevated D-dimer.

lab findings associated with ischemic bowel

CT angiography (CTA)

diagnostic test of choice for ischemic bowel

ischemic bowel on XR

Bowel wall thickening, pneumatosis intestinalis (air in wall).

Portal venous gas.

Thumbprinting sign (submucosal edema/hemorrhage).